Damper with bypass, method for producing damper

Abstract

The present invention relates to a damper comprising: a pressure tube filled with a damping fluid; a piston mounted in the pressure tube so as to be displaceable along a stroke axis, the piston dividing the pressure tube into a front chamber in front of the piston along the stroke axis and a rear chamber behind the piston along the stroke axis; a piston rod fastened to the piston, in which the piston rod is drawn out of the pressure tube through the rear chamber along a stroke axis; and a bypass arranged outside the pressure tube, where the bypass connects the front chamber to the rear chamber in a damping fluid conducting manner. The bypass is at least partially bounded by a bypass wall, where the bypass wall is elastically deformable into the bypass to accommodate a volume of damping fluid displaced by the piston rod when the piston rod is inserted into the pressure tube.

Description

Technical Field

[0001] The present invention relates to a damper comprising: a pressure tube filled with a damping fluid; a piston displaceably mounted in the pressure tube along a stroke axis, wherein the piston divides the pressure tube into a front chamber along the stroke axis in front of the piston and a rear chamber along the stroke axis behind the piston; a piston rod fastened to the piston, wherein the piston rod extends from the pressure tube through the rear chamber along the stroke axis; and a bypass disposed outside the pressure tube, wherein the bypass connects the front chamber to the rear chamber in a manner that conducts the damping fluid.

[0002] The present invention also relates to a method for manufacturing a damper. Existing technology

[0003] US Patent 2019 / 106849 A1 discloses a hydraulic damper with a pressure tube designed as a double tube. Hydraulic oil flows from the front chamber of the pressure tube in front of the piston to the rear chamber of the pressure tube behind the piston between the walls of the double tubes. For the piston rod, which exits the damper through the rear chamber, to move into the pressure tube, the space between the pressure tubes or walls must contain compressible gas in addition to the hydraulic oil. However, the gas must not accumulate in the front chamber or cause foaming of the hydraulic oil, as this would impair the damping effect of the damper. Therefore, the damper must be kept aligned with the rear chamber above the front chamber and must not be subjected to excessive movement or vibration. Rapid piston movement within the damper must also be avoided, as this could lead to foaming. Therefore, the possible applications of the damper from US 2019 / 106849 A1 are limited.

[0004] The hydraulic damper described in DE 33 21 680 A1 also includes a pressure tube designed as a double tube. Here, the intermediate space between the walls of the pressure tube serves only as a compensation space, containing compressible gas and a portion of hydraulic oil. This reduces the risk of bubbling, but the damper still needs to maintain a specific orientation to prevent gas from entering the front chamber. Furthermore, according to DE 33 21 680 A1, the piston of the damper must have a bypass, allowing hydraulic oil to flow from the front chamber to the rear chamber. This requires a piston with a complex construction.

[0005] Publications DE 42 12 078 A1 and DE 22 45 258 A1 disclose a hydraulic damper including a compensation space disposed on the outside of the pressure tube of the damper, the compensation space being defined by an elastic sleeve. This means that, according to DE 42 12 078 A1 and DE 22 45 258 A1, the damper can be completely filled with hydraulic oil, so that problems caused by additional gas do not occur. However, these dampers also require a bypass located within their pressure tube, allowing hydraulic oil to flow from the front chamber to the rear chamber, which complicates the manufacture of the damper. Furthermore, the bypass within the pressure tube makes it difficult for the damper to provide resistance during high-speed piston rod insertion. Such resistance is necessary, for example, for dampers used as speed bumps, according to US 2019 / 106849 A1 or publication DE 10 2020 109 215 A1. Summary of the Invention

[0006] Technical Purpose

[0007] The object of the present invention is to provide a damper with a simple construction that can be used in a variety of ways, particularly independent of the orientation of the damper and / or for a wide range of piston movement speeds in the pressure tube of the damper.

[0008] Technical solution

[0009] This invention provides a damper that achieves the technical objective. The damper comprises:

[0010] a. A pressure tube filled with damping fluid;

[0011] b. A piston, which is displaceably mounted in the pressure tube along a stroke axis, wherein the piston divides the pressure tube into a front chamber in front of the piston along the stroke axis and a rear chamber behind the piston along the stroke axis;

[0012] c. A piston rod, fastened to the piston, wherein the piston rod is led out from the pressure tube through the rear chamber along the stroke axis; and

[0013] d. Bypass, the bypass being disposed outside the pressure pipe, wherein the bypass connects the front chamber to the rear chamber in a manner that conducts the damping fluid;

[0014] in

[0015] e. The bypass is defined at least partially by a sleeve wall extending about the stroke axis of the pressure tube and at least partially by a bypass wall, wherein the bypass wall is elastically deformable into the bypass to accommodate a volume of the damping fluid displaced by the piston rod when the piston rod is inserted into the pressure tube.

[0016] This objective is also achieved by a method for manufacturing a damper. The method includes the following steps:

[0017] a. Provide a pressure pipe for containing damping fluid;

[0018] b. Secure the piston rod to the piston;

[0019] c. Arranging the piston in the pressure tube such that the piston can be displaced along the stroke axis, and dividing the pressure tube into a front chamber along the stroke axis in front of the piston and a rear chamber along the stroke axis behind the piston, wherein the piston rod is led out from the pressure tube through the rear chamber along the stroke axis; and

[0020] d. A bypass is arranged outside the pressure tube such that the bypass connects the front chamber to the rear chamber in a manner that conducts the damping fluid, wherein the bypass is at least partially defined by a bypass wall that is elastically deformable into the bypass to accommodate a volume of the damping fluid displaced by the piston rod when the piston rod is inserted into the pressure tube.

[0021] The damper includes at least one pressure tube filled with a damping fluid. The damping fluid is, for example, hydraulic oil. The pressure tube is, for example, a hollow cylinder, and / or made of metal, particularly steel.

[0022] The damper includes at least one piston mounted in a pressure tube to allow displacement along a stroke axis. The piston is, for example, cylindrical and / or made of metal, particularly steel. The stroke axis is, for example, coaxial with the piston and / or the pressure tube.

[0023] The piston divides the pressure tube into at least one front chamber along the stroke axis in front of the piston and at least one rear chamber along the stroke axis behind the piston. Preferably, the piston separates the front and rear chambers to form an impermeable seal against the damping fluid. Preferably, the piston carries at least one sealing element that seals the piston to the inside of a sleeve wall extending around the stroke axis of the piston.

[0024] The damper includes at least one piston rod fastened to a piston, wherein the piston rod is led out of a pressure tube through a rear chamber along a stroke axis (e.g., coaxial with the stroke axis). Preferably, the piston rod is led out of the pressure tube by at least one guiding and sealing unit, wherein the guiding and sealing unit guides the piston rod along the stroke axis and closes the pressure tube to form an impermeable seal against the damping fluid.

[0025] The damper includes at least one bypass disposed outside the pressure tube, wherein the bypass connects the front chamber to the rear chamber in a manner that conducts damping fluid. The bypass advantageously allows damping fluid displaced by the piston to flow from the front chamber into the rear chamber or from the rear chamber into the front chamber, depending on the direction of piston movement.

[0026] Therefore, the bypass causes the piston to move along the stroke axis.

[0027] The bypass is at least partially defined by a bypass wall, which is elastically deformable into the bypass to accommodate a volume of damped fluid displaced by the piston rod when the piston rod is inserted into the pressure tube.

[0028] Preferably, the bypass is partially defined by a sleeve wall extending around the stroke axis of the pressure pipe. By using the sleeve wall to define the bypass, additional material used for defining the bypass is saved.

[0029] Beneficial effects

[0030] Due to the elastic deformability of the bypass wall, the bypass can absorb a certain volume of damping fluid as the piston rod is inserted into the pressure tube, allowing the piston rod to be inserted without the need for the damper to contain compressible gas or other measures for volume compensation. Therefore, the pressure tube and bypass can be completely filled with damping fluid, eliminating the risk of gas accumulation in the pre-chamber or foaming of the damping fluid. Consequently, the damper is particularly versatile, especially independent of its orientation, and can be used for a wide range of speeds for motions requiring damping.

[0031] The bypass wall can be placed directly or indirectly against the sleeve wall of the pressure tube along almost its entire length, and form the outer wall of the damper.

[0032] Because the bypass provides both volume compensation and connection between the front and rear chambers, these functions do not require additional components, allowing the damper, and especially the damper piston, to be constructed with exceptional simplicity.

[0033] According to US 2019 / 106849 A1 or according to publication DE 10 2020 109 215 A1, the aforementioned advantages are particularly important when the damper is used as a damper for speed bumps. In this application, the gas in the damper is particularly problematic because, depending on the vehicle speed traveling over the speed bump, the movement of the speed bump must be damped over a wide speed range. Furthermore, due to the damper's mounting position at the speed bump, it is particularly difficult to remove the gas already collected in the front chamber by fully inserting the piston rod.

[0034] Description of implementation scheme type

[0035] The bypass wall is preferably formed of at least one hose. The bypass wall is particularly easy to implement as a hose.

[0036] The pressure tube is preferably arranged within a hose, such that the bypass extends between the sleeve wall and the hose. For example, the pressure tube is coaxially located within the hose. In this way, the bypass can be formed particularly simply and with minimal material, for example, by pulling the hose through the pressure tube and sealing it to the sleeve wall at the end of the hose. To allow damping fluid to flow from the anterior and posterior chambers into the bypass, the pressure tube may have several openings through the sleeve wall.

[0037] By enclosing the pressure tube within a flexible hose, the hose forming the outer wall can advantageously protect the pressure tube, for example, from mechanical and / or chemical stresses, particularly in corrosive environments. When dampers are used at speed bumps or in vehicle chassis, corrosive environments may arise, such as from road salt and condensation. To protect the portions of the damper not covered by the hose from corrosion, the damper is coated with an anti-corrosion coating during the impregnation process, for example, after the hose has been attached to the pressure tube.

[0038] The damper preferably includes a spacer for separating the bypass wall from the sleeve wall. In other words, the damper includes a spacer.

[0039] Due to the elasticity of the bypass wall, especially when the piston rod is positioned far from the pressure tube, the bypass wall can adhere to the sleeve wall, resulting in only a small amount of damping fluid in the bypass. This can obstruct the bypass, preventing the damping fluid from flowing from the front chamber to the rear chamber and back, thus trapping the piston in the pressure tube or creating a negative pressure behind the piston, which can cause air to flow into the pressure tube from the outside. These problems are addressed by a spacer. As a supplement to or alternative to the spacer, damping fluid can be filled into the pressure tube and bypass at a sufficiently high pressure to prevent the bypass wall from adhering to the sleeve wall.

[0040] The spacer preferably includes at least one sleeve, such as a hollow cylindrical sleeve, arranged between the bypass wall and the sleeve wall and having a plurality of channels for connecting the front chamber to the rear chamber in a manner that conducts damping fluid. The channels are formed, for example, by grooves in the surface of the sleeve, particularly the inner surface. The sleeve preferably includes a plurality of notches, such as holes and / or perforations, for allowing damping fluid to pass through, particularly radially to the stroke axis, through the sleeve. Advantageously, the notches allow damping fluid to pass from the region between the sleeve and the sleeve wall, particularly from the grooves, into the region between the sleeve and the bypass wall, such that the region between the sleeve and the bypass wall can be used as a compensation space to accommodate damping fluid displaced from the pressure tube. Advantageously, the sleeve can be designed independently of the requirements for the presence of the sleeve wall and / or the bypass wall.

[0041] For example, sleeve materials that are particularly flexible, lightweight, cost-effective, and / or easy to process can be selected. The sleeve is preferably made of an elastomer, preferably a thermoplastic elastomer, and particularly preferably a polyurethane-based thermoplastic elastomer.

[0042] The flexible sleeve can advantageously accommodate a certain volume of damping fluid in the bypass, thereby increasing the flow rate through the bypass. If the spacer is formed by the sleeve, the sleeve wall and bypass wall can be formed by standard components to minimize the cost of manufacturing the damper.

[0043] An alternative embodiment specifies that the spacer preferably includes at least one structured portion of the surface of the bypass wall for spaced out from the sleeve wall, the surface facing the sleeve wall. For example, the bypass wall with the structured portion is additively manufactured, particularly by 3D printing. Because the spacer is designed as a structured portion of the bypass wall, no separate component is required, making the damper particularly easy to assemble. However, in addition to the sleeve described above, a structured portion of the bypass wall can also be provided.

[0044] The structured portion of the bypass wall's surface facing the housing wall preferably includes a plurality of protrusions and / or a plurality of grooves for connecting the anterior chamber to the posterior chamber in a manner that conducts damped fluid. The shape, size, and / or spacing of the protrusions are preferably selected such that the bypass wall cannot abut against the bypass and housing walls.

[0045] The sleeve and / or bypass wall preferably includes several circumferential grooves extending around the stroke axis, and preferably includes several axial grooves extending along the stroke axis, which are connected to the circumferential grooves in a manner that conducts damping fluid. This allows the circumferential grooves to distribute the damping fluid exiting the pressure pipe through the openings to the axial grooves, and all axial grooves to facilitate the conduction of damping fluid from the front chamber to the rear chamber and back.

[0046] The damper preferably includes several openings for connecting the anterior and posterior chambers to a bypass in a manner that conducts damping fluid.

[0047] The opening is preferably formed in the sleeve wall. For example, the opening can be simply designed as a hole and / or a punch.

[0048] Alternatively, it can be envisioned that the openings to the bypass in both chambers be located in the connecting component, where it is necessary to ensure a seal between the connecting component and the pressure pipe and the bypass wall.

[0049] Alternatively, it can be envisioned that the pressure pipe be sealed using a bypass wall or sleeve, and that the opening be arranged in a cup-shaped area of ​​the bypass wall or sleeve, which is configured to seal the pressure pipe from the front.

[0050] Preferably, the opening is connected to the circumferential groove in a manner that conducts damping fluid.

[0051] The bypass wall and / or sleeve preferably include at least one sealing surface, wherein the sealing surface is fastened to, preferably clamped, glued, welded, and / or vulcanized to the sleeve wall to form a fluid-impermeable seal against the damping fluid. The sealing surface is clamped to the sleeve wall, for example, by a hose clamp or protective tube that presses the bypass wall and / or sleeve against the sleeve wall. The sealing surface preferably does not have structured portions, channels, or notches. (Especially unstructured) sealing surfaces advantageously prevent the damping fluid from escaping from the bypass between the bypass wall and / or sleeve and the sleeve wall.

[0052] The bypass wall is preferably made of an elastomer, preferably a thermoplastic elastomer, and particularly preferably a polyurethane-based thermoplastic elastomer. Elastomers, such as vulcanized rubbers of natural rubber or silicone rubber, especially vulcanized rubbers of acrylonitrile butadiene rubber, can advantageously provide the necessary elasticity for the bypass wall. Thermoplastic elastomers have the added advantage of being plastically deformable upon heating to form structured portions on the surface of the bypass wall. In particular, bypass walls with structured portions can be manufactured from thermoplastic elastomers using additive methods (e.g., by 3D printing). Both polyurethane-based thermoplastic elastomers and vulcanized rubbers of acrylonitrile butadiene rubber offer the advantage of high chemical resistance. The bypass wall, for example, has a Shore A hardness of 95.

[0053] The damper preferably includes at least one foot valve for regulating the flow of damping fluid between the pre-chamber and the bypass, wherein the foot valve causes flow resistance to the flow, which depends on the flow direction and / or flow velocity.

[0054] For example, the foot valve is designed to cause small flow resistance for flow from the bypass to the pre-chamber and for flow from the pre-chamber to the bypass at flow velocities less than the switching speed, and large flow resistance, particularly obstruction, for flow from the pre-chamber to the bypass at flow velocities greater than or equal to the switching speed. Therefore, the damper dampens the slow insertion movement of the piston rod into the pressure tube and the movement of the piston rod extending out of the pressure tube with a small damping force, and dampens the rapid insertion movement of the piston rod into the pressure tube with a large damping force. Such speed-dependent and direction-dependent damping forces are particularly advantageous for damping the movement of speed bumps, as described in US 2019 / 106849 A1 or DE 10 2020 109 215 A1.

[0055] The damper preferably includes: at least one overload passage through the piston, the overload passage connecting the front chamber to the rear chamber in a manner that conducts damping fluid; and an overload valve that closes the overload passage when the pressure difference between the front and rear chambers is less than the overload pressure, and opens the overload passage when the pressure difference is greater than or equal to the overload pressure.

[0056] During rapid piston movement within the pressure tube, for example due to rapid piston rod insertion into the pressure tube, the foot valve preferably causes high flow resistance in the bypass of the damping fluid or completely blocks the damping fluid, thus braking or stopping the piston. If a large force is introduced into the damper via the piston rod in this state, this force creates a high pressure differential, causing external air to flow into the pressure tube on the low-pressure side of the piston. Furthermore, this force may damage the damper or associated components while the piston is blocked. An overload passage with an overload valve allows the damping fluid to exchange between the front and rear chambers at a pressure differential higher than the overload pressure, thereby moving the piston and reducing the pressure differential, thus preventing damage to the damper and associated components.

[0057] The damper preferably includes a spring element, such as a helical spring, connected to the piston and / or piston rod and the pressure tube to facilitate extension of the piston rod out of the pressure tube. If the damper does not have such a spring element, extension of the piston rod can be achieved solely by the elastic restoring force of the bypass wall, which pushes the damping fluid back from the bypass into the pressure tube, thus extending the piston rod out of the pressure tube. If the restoring force of the bypass wall is insufficient for extension, for example because the piston rod bears the weight of a speed bump, a spring element can ensure extension.

[0058] Methods for manufacturing a damper include providing a pressure tube for containing damping fluid. The possible implementations and advantages described for the damper also apply to this method.

[0059] The method involves fastening the piston rod to the piston.

[0060] The method includes arranging a piston in a pressure tube such that the piston can be displaced along a stroke axis, and dividing the pressure tube into a front chamber along the stroke axis in front of the piston and a rear chamber along the stroke axis behind the piston, wherein a piston rod is led out of the pressure tube along the stroke axis through the rear chamber.

[0061] The method includes arranging a bypass outside the pressure tube such that the bypass connects the front chamber to the rear chamber in a manner that conducts damping fluid, wherein the bypass is at least partially defined by a bypass wall that is elastically deformable into the bypass (140) to accommodate a volume of damping fluid displaced by the piston rod when the piston rod is inserted into the pressure tube. Attached Figure Description

[0062] Other advantages, objects and features of the present invention will be explained with reference to the following description and drawings, in which exemplary subjects according to the invention are illustrated.

[0063] Figure 1 An embodiment of a damper according to the invention, in which a portion of the piston rod is inserted, is schematically shown.

[0064] Figure 2 schematically shown Figure 1 One of the implementation schemes is a damper with an extended piston rod.

[0065] Figure 3A and Figure 3B An example of the bypass wall of the damper according to the present invention is shown.

[0066] Figure 4A and Figure 4B An example of a sleeve for a damper according to the present invention is shown. Detailed Implementation

[0067] Figure 1

[0068] Figure 1 As a schematic longitudinal section along the stroke axis H of the damper 100, an embodiment of the damper 100 according to the invention is schematically shown, wherein the piston rod 130 is partially inserted into the pressure tube 110 of the damper 100.

[0069] The damper 100 shown includes a pressure tube 110 filled with damping fluid (not shown) and a piston 120 mounted in the pressure tube 110 that is displaceable along the stroke axis H, wherein the piston 120 divides the pressure tube 110 into a front chamber 111 along the stroke axis H in front of the piston 120 and a rear chamber 112 along the stroke axis H behind the piston 120.

[0070] The damper 100 shown includes a piston rod 130 fastened to a piston 120, which extends from a pressure tube 110 through a rear chamber 112 and a guide and seal unit 170 along the stroke axis H. The guide and seal unit 170 closes one end of the pressure tube 110 to form a fluid-impermeable seal against the damping fluid. At the end of the pressure tube 110 opposite the guide and seal unit 170 along the stroke axis H, a sealing element 180 closes the pressure tube 110 to form a fluid-impermeable seal against the damping fluid.

[0071] The damper 100 shown includes a bypass 140 disposed outside the pressure tube 110, wherein the bypass 140 connects the front chamber 111 to the rear chamber 112 in a manner that conducts damping fluid. For this purpose, the damper 100 includes a plurality of openings 114 through the sleeve wall 113 of the pressure tube 110 for connecting the front chamber 111 and the rear chamber 112 to the bypass 140 in a manner that conducts damping fluid.

[0072] Bypass 140 is partially defined by bypass wall 141. Figure 1 In the state of the damper 100 shown, by accommodating a certain volume of damping fluid displaced by the piston rod 130 when the piston rod 130 is inserted into the pressure tube 110, the bypass wall 141 elastically deforms radially outward from the stroke axis H into the bypass 140.

[0073] The bypass wall 141 is formed of a flexible hose, in which a pressure tube 110 is arranged, such that the bypass 141 extends between the sleeve wall 113 and the flexible hose. The bypass wall 141 may be placed directly or indirectly against the sleeve wall 113 along almost its entire length (see...). Figure 2 ), and form the outer wall of the damper 100.

[0074] At the end of the pressure tube 110 along the travel axis, a bypass wall 141 formed by a hose is fastened to the sleeve wall 113 to form an impermeable seal for the damping fluid, so that the damping fluid cannot escape from the bypass 140 into the surrounding environment of the damper 100.

[0075] The damper 100 shown includes a bottom valve 150 for regulating the flow of damping fluid between the front chamber 111 and the bypass 140, wherein the bottom valve 150 causes flow resistance that depends on the flow direction and flow velocity.

[0076] The damper 100 shown includes: at least one overload passage 121 passing through the piston 120, the overload passage connecting the front chamber 111 to the rear chamber 112 in a manner that conducts damping fluid; and an overload valve 122 that closes the overload passage 121 when the pressure difference between the front chamber 111 and the rear chamber 112 is less than the overload pressure, and opens the overload passage 121 when the pressure difference is greater than or equal to the overload pressure.

[0077] The damper 100 shown includes a spring element 160, such as a helical spring, wherein the spring element 160 is connected to the piston 120 and the pressure tube 110 to facilitate the extension of the piston rod 130 out of the pressure tube 110.

[0078] Figure 2

[0079] Figure 2 As a schematic longitudinal section along the stroke axis H of the damper 100, it is schematically shown Figure 1 An embodiment of the damper 100, wherein the piston rod 130 extends out of the pressure tube 110.

[0080] Because the piston rod 130 extends out of the pressure tube 110, therefore in Figure 1 The damper 100 shown is in a state where a certain volume of damping fluid is in the bypass 140. Figure 2 The damper 100 shown is in the pressure cylinder 110. Therefore, the bypass wall 141 is elastically reset radially toward the stroke axis H, so that the bypass wall 141 abuts against the sleeve wall 113 of the pressure cylinder 110.

[0081] In order to allow the damping fluid to still flow through the opening 114 in the sleeve wall 113 and through the bypass (not visible) from the front chamber 111 into the rear chamber 112 and back, the surface of the bypass wall 141 has a structure (not shown) as, for example, a spacer or spacer through which the damping fluid can flow between the sleeve wall 113 and the bypass wall 141, the surface of which faces the sleeve wall 113.

[0082] Figure 3A and Figure 3B

[0083] Figure 3A and Figure 3B As a cross section transverse to the stroke axis H of the damper 100 ( Figure 3A ) and as a longitudinal section along the stroke axis H ( Figure 3B The bypass wall 141 of the damper 100 according to the invention is shown by way of example. The bypass wall 141 is designed, for example, as a flexible hose, particularly made of an elastomer, and / or is hollow cylindrical in shape and / or arranged coaxially with the stroke axis H. For clarity, other components of the damper 100 are not shown. Figure 3A and Figure 3B As shown in the image.

[0084] The bypass wall 141 shown includes a structured portion of the surface of the sleeve wall 113 facing the pressure tube 110 (not shown) of the damper 100 (particularly the inner surface of the bypass wall 141) for spaced apart from the sleeve wall 113.

[0085] The structured portion of the surface of the bypass wall 141 facing the sleeve wall 113 includes a plurality of grooves for connecting the front chamber 111 of the pressure tube 110 of the damper 100 to the rear chamber 112 of the pressure tube 110 in a manner that conducts damping fluid, wherein the structured portion of the pressure tube 110 serves as a spacer or spacer for separating the bypass wall 141 from the sleeve wall 113.

[0086] The bypass wall 141 has several grooves including several circumferential grooves 144 extending around the travel axis H, wherein the circumferential grooves 144 are preferably conductively connected to an opening through the sleeve wall 113 for connecting the pre-chamber 111 and / or the rear chamber 112 to the bypass in a manner that conducts damping fluid. For example, the bypass wall 141 has a first circumferential groove 144 and a second circumferential groove 144, the first circumferential groove being connected to a first end of the pre-chamber 111 near the bypass wall 141 via the opening through the sleeve wall 113, and the second circumferential groove being connected to a second end of the rear chamber 112 near the bypass wall 141 via the opening through the sleeve wall 113.

[0087] The grooves include several, particularly multiple, axial grooves 145 extending along the travel axis H, which are connected to the circumferential grooves 144 in a manner that conducts damping fluid.

[0088] The bypass wall 141 includes at least one sealing surface 143, particularly the sealing surface 143 at each of its ends. The sealing surface 143 is fastened to the sleeve wall 113 to form an impermeable seal against damping fluid and has no structured portion.

[0089] Figure 4A and Figure 4B

[0090] Figure 4A and Figure 4B As a cross section transverse to the stroke axis H of the damper 100 ( Figure 4A ) and as a longitudinal section along the stroke axis H ( Figure 4B The sleeve 146 of the damper 100 according to the invention is shown by way of example. The sleeve 146 is preferably hollow cylindrical in shape and / or arranged coaxially with the stroke axis H. For clarity, other components of the damper 100 are not shown. Figure 4A and Figure 4B As shown in the image.

[0091] The sleeve 146 includes a number of channels, such as, particularly, a number of grooves in the inner surface of the sleeve 146, for connecting the front chamber 111 of the pressure tube 110 of the damper 100 to the rear chamber 112 of the pressure tube 110 in a manner that conducts damping fluid.

[0092] Sleeve 146 serves as a spacer or spacer between bypass wall 141 and sleeve wall 113, and has several notches 147, particularly for allowing damping fluid to pass through the sleeve 146.

[0093] The sleeve 146 has several grooves including several circumferential grooves 144 extending around the stroke axis H, wherein the circumferential grooves 144 are preferably conductively connected to an opening in the sleeve wall 113 through the pressure tube 110 of the damper 100 for connecting the front chamber 111 and / or the rear chamber 112 to a bypass in a manner that conducts damping fluid. For example, the sleeve 146 has a first circumferential groove 144 and a second circumferential groove 144, the first circumferential groove being connected to a first end of the front chamber 111 near the opening of the sleeve 146 through the sleeve wall 113, and the second circumferential groove being connected to a second end of the rear chamber 112 near the opening of the sleeve 146 through the sleeve wall 113.

[0094] The grooves include several, particularly multiple, axial grooves 145 extending along the travel axis H, which are connected to the circumferential grooves 144 in a manner that conducts damping fluid.

[0095] The sleeve 146 includes at least one sealing surface 143, particularly at each of its ends. The sealing surface 143 is fastened to the sleeve wall 113 to form an impermeable seal against damping fluid and has no channels or gaps.

[0096] One embodiment (not shown) provides the aforementioned opening 114 not arranged in the sleeve wall 113 but in the connecting member (not shown), through which the bypass wall 141 and / or sleeve 146 are sealed to the pressure pipe 110.

[0097] Alternatively, it is also envisioned that the opening be integrated into the guide and sealing unit 170 or the closing element 180. The sealing and securing of the bypass wall 114 must be designed accordingly.

[0098] Another alternative embodiment of the invention provides a bypass wall or the aforementioned sleeve that functions as a sealing element for the pressure tube 110. For this purpose, one end face of the bypass wall or sleeve is cup-shaped and seals the pressure tube 110. In this case, the separate sealing element 180 can be omitted.

[0099] Therefore, the opening for the fluid conduction connection between the anterior chamber and the bypass 140 can be arranged in the cup-shaped area of ​​the bypass wall or sleeve.

Claims

1. A damper (100), comprising: a. a pressure tube (110) filled with a damping fluid; b. a piston (120) displaceably mounted in the pressure tube (110) along a stroke axis (H), wherein the piston (120) divides the pressure tube (110) into a front chamber (111) in front of the piston (120) along the stroke axis (H) and a rear chamber (112) behind the piston (120) along the stroke axis (H); c. a piston rod (130) fastened to the piston (120), wherein the piston rod (130) leads out of the pressure tube (110) through the rear chamber (112) along the stroke axis (H); and d. a bypass (140) arranged outside the pressure tube (110), wherein the bypass (140) connects the front chamber (111) to the rear chamber (112) in a manner that conducts the damping fluid; wherein e. the bypass (140) is at least partially delimited by a sleeve wall (113) of the pressure tube (110) extending around the stroke axis (H) and at least partially by a bypass wall (141), wherein the bypass wall (141) is elastically deformable into the bypass (140) to accommodate a volume of the damping fluid displaced by the piston rod (130) when the piston rod (130) is inserted into the pressure tube (110).

2. The damper (100) according to claim 1, wherein the bypass wall (141) is formed by a hose.

3. The damper (100) according to claim 2, wherein the pressure tube (110) is arranged in the hose such that the bypass (140) extends between the sleeve wall (113) and the hose.

4. The damper (100) according to claim 2 or 3, wherein the damper (100) comprises spacing means for spacing the bypass wall (141) from the sleeve wall (113).

5. The damper (100) according to claim 4, wherein the spacing means comprise a sleeve (146) arranged between the bypass wall (141) and the sleeve wall (113) and having several passages, preferably several slots, for connecting the front chamber (111) to the rear chamber (112) in a manner that conducts the damping fluid, wherein the sleeve (146) preferably has several notches (147) for the damping fluid to pass through the sleeve (146).

6. The damper (100) according to claim 4 or 5, wherein the spacing means comprise a structuring of a surface of the bypass wall (141) for spacing the bypass wall (141) from the sleeve wall (113), the surface facing the sleeve wall (113).

7. The damper (100) according to claim 6, wherein the structuring of the surface of the bypass wall (141) comprises several protrusions and / or several grooves for connecting the front chamber (111) to the rear chamber (112) in a manner that conducts the damping fluid, the surface facing the sleeve wall (113).

8. Damper (100) according to claim 5 or 7, wherein the several grooves of the bypass wall (141) and / or of the sleeve (146) comprise several circumferential grooves (144) extending around the stroke axis (H), and wherein the several grooves comprise several axial grooves (145) extending along the stroke axis (H), the axial grooves being connected to the circumferential grooves (144) in a manner that conducts the damping fluid.

9. Damper (100) according to any one of claims 1 to 8, wherein the damper (100) comprises several openings (114) for connecting the front chamber (111) and the rear chamber (112) to the bypass (140) in a manner that conducts the damping fluid.

10. Damper (100) according to claim 8, wherein the openings (114) are formed in the sleeve wall (113).

11. Damper (100) according to claim 9 or 10, wherein the openings (114) are connected to the circumferential grooves (144) in a manner that conducts the damping fluid.

12. Damper (100) according to any one of claims 1 to 11, wherein the bypass wall (141) comprises a sealing surface (143), a. wherein the sealing surface (143) for the damping fluid is sealingly attached to the sleeve wall (113), preferably clamped, glued, welded and / or vulcanized onto the sleeve wall (113); and b. wherein the sealing surface (143) is free of structurings, channels or recesses.

13. Damper (100) according to claim 5 and any one of claims 6 to 11, wherein the bypass wall (141) and / or the sleeve (146) comprises a sealing surface (143), a. wherein the sealing surface (143) for the damping fluid is sealingly attached to the sleeve wall (113), preferably clamped, glued, welded and / or vulcanized onto the sleeve wall (113); and b. wherein the sealing surface (143) is free of structurings, channels or recesses.

14. Damper (100) according to any one of claims 1 to 13, wherein the bypass wall (141) is made of an elastomer, preferably of a thermoplastic elastomer, particularly preferably of a polyurethane-based thermoplastic elastomer.

15. Damper (100) according to any one of claims 1 to 14, wherein the damper (100) comprises a bottom valve (150) for regulating a flow of the damping fluid between the front chamber (111) and the bypass (140), wherein the bottom valve (150) induces a flow resistance of the flow, the flow resistance depending on a flow direction and / or a flow velocity of the flow.

16. Damper (100) according to any one of claims 1 to 15, wherein the damper (100) comprises: a. an overload passage (121) through the piston (120) connecting the front chamber (111) to the back chamber (112) in a manner that conducts the damping fluid; and b. an overload valve (122) closing the overload passage (121) when a pressure difference between the front chamber (111) and the back chamber (112) is smaller than an overload pressure and opening the overload passage (121) when the pressure difference is greater than or equal to the overload pressure.

17. Damper (100) according to any one of claims 1 to 16, wherein the damper (100) comprises a spring element (160), wherein the spring element (160) is connected to the piston (120) and / or the piston rod (130) and the pressure tube (110) to facilitate extending the piston rod (130) out of the pressure tube (110).

18. Method for manufacturing a damper (100) according to any one of claims 1 to 17, comprising the following steps: a. providing a pressure tube (110) for containing a damping fluid; b. fastening a piston rod (130) to a piston (120); c. arranging the piston (120) in the pressure tube (110) such that the piston (120) is displaceably mounted along a stroke axis (H) and divides the pressure tube (110) into a front chamber (111) in front of the piston (110) along the stroke axis (H) and a back chamber (112) behind the piston (120) along the stroke axis (H), wherein the piston rod (130) is led out of the pressure tube (120) through the back chamber (112) along the stroke axis (H); and d. arranging a bypass (140) outside the pressure tube (110) such that the bypass (140) connects the front chamber (111) to the back chamber (112) in a manner that conducts the damping fluid, wherein the bypass (140) is at least partially delimited by a bypass wall (141) that is elastically deformable into the bypass (140) to accommodate a volume of the damping fluid displaced by the piston rod (130) when the piston rod (130) is inserted into the pressure tube (110).

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